For example, in the event of head-on collision or rear end collision of a passenger vehicle and a large vehicle such as a truck, due to a difference in installation heights of strength members such as cross members provided in the vehicles, the passenger vehicle may become wedged under the large vehicle. Therefore, in the related art, an underrun protector is provided at the front part and the rear part of the large vehicle in accordance with an installation height of a strength member of the passenger vehicle. The underrun protector is an example of an end structure of a vehicle. In addition, underrun protectors include a front underrun protector (FUP) provided at the front of a vehicle and a rear underrun protector (RUP) provided at the rear of a vehicle.
It is necessary for such an underrun protector to prevent the passenger vehicle from becoming wedged under the large vehicle and to exhibit a collision energy absorption effect due to a crushable zone provided at the front or rear part of the passenger vehicle. Therefore, there is a higher demand for the underrun protector to have load resistance performance to generate a reaction force by which the passenger vehicle that collides with the large vehicle is cast aside rather than for an effect of absorbing the collision energy generated when collision with the passenger vehicle occurs.
For example, techniques related to underrun protectors are disclosed in Patent Literature 1 to 3. Such underrun protectors have a structure in which a beam that extends in a vehicle width direction is fastened to a vehicle body frame with a bracket or a stay (support) therebetween.
In addition, in the underrun protector disclosed in Patent Literature 4, a reinforcing member is provided to bridge a frame attachment part attached to a vehicle body frame and a beam attachment surface (a main body attachment part) attached to a beam in a plan view. Thus, improvement of the load resistance performance is attempted.